Ergonomic platform truck

ABSTRACT

A dual ergonomic platform truck includes a frame assembly having a pair of first and second segments, a pair of guide rods each having a first end connected to one of the first segments and a second end connected to one of the second segments. A pair of platform assemblies are moveable along the pair of guide rods respectively. Each platform assembly includes a deck guide that receives the guide rod and a platform that is connected to the deck guide and is constructed to hold items. Each platform assembly also includes a first linear bearing that is received within the deck guide and a spring support bracket connected to the deck guide. A pair of springs are used to lift the pair of platform assemblies respectively. Each spring is connected to the first and second segments of the frame assembly. The platform truck may also include a self-aligning platform assembly. A handtruck includes a frame assembly, at pair of wheels, a guide rod, a platform assembly that is moveable along the guide rod, and a spring that provides a lifting force to the platform assembly. The handtruck may also include a latch system for use in preventing the platform assembly from moving along the guide rod and a hydraulic cylinder or frictional dampers for use in damping (slowing) the spring force as it is applied to the platform assembly.

This application is a Continuation-In-Part of U.S. patent applicationSer. No. 08/843,802, filed Apr. 21, 1997, now U.S. Pat. No. 6,035,973.

BACKGROUND OF THE INVENTION

1. Field of Invention

The present invention pertains to methods and apparatuses for adjustingthe height of parts or other items for use by an operator and moreparticularly to methods and apparatuses for providing an ergonomicplatform truck including a platform assembly that is moveable along apair of guide rods.

2. Description of the Related Art

It is known to provide a vertical adjustment mechanism for maintainingparts at a vertical position within a parts bin.

A problem commonly encountered in the art deals with a reliable meansfor maintaining a platform, which holds the parts, at a requiredvertical position when parts are removed or added.

Another problem encountered in the art deals with the position of thelifting means used to lift the platform. Typically, the lifting means ispositioned directly below the platform. Such positioning does not takefull advantage of the space under the platform.

Another problem encountered in the art deals with the stability of theapparatus. Often the platform is connected to the lifting means and theparts bin in only one or a few places.

Still another problem in the art relates to inconsistencies in theplatform truck. These inconsistencies may be caused by inaccuracies inthe material or manufacturing in the fabrication of the ergonomicplatform truck. Inconsistencies to the platform truck may also be causedby forces exerted on the truck, such as by the collision of the truckwith a wall or another truck. All such inconsistencies can createmisalignment problems for the platform.

The present invention provides methods and apparatuses for reducingthese problems. The difficulties inherent in the art are thereforeovercome in a way, which is simple and efficient, while providing betterand more advantageous results.

SUMMARY OF THE INVENTION

It is an object of the present invention to eliminate injuries caused bybending to remove parts from a parts bin.

It is another object of the present invention to disclose a device forand a method of vertically adjusting parts in a parts bin to minimizethe bending required to remove a part from the parts bin.

It is another object of the present invention to disclose a device forand method of adjusting the height of parts in a parts bin that is underthe control of a human operator.

It is another object of the present invention to disclose a device forand method of vertically adjusting the height of parts in a parts binthat is under the control of an electronic device.

It is another object of the present invention to disclose a device forand method of vertically adjusting parts in a parts bin by a mechanical,hydraulic, or pneumatic mechanism.

It is another object of the present invention to disclose a device forand method of vertically adjusting parts in a parts bin that isportable.

It is another object of the present invention to disclose a device forand method of vertically adjusting parts in a parts bin that isremovable from the parts bin.

It is another object of the present invention to disclose a device forand a method of vertically adjusting parts in a parts bin that fits intoany size parts bin and vertically adjusts parts of any size or weight.

It is another object of the present invention to disclose a device forand method of vertically adjusting parts in a parts bin that is strong,lightweight, long lasting, economic, and ergonomic.

It is another object of the present invention to disclose a device forand method of vertically adjusting parts in a parts bin using a springhaving a spring constant chosen and matched to the weight of the partsstored in the parts bin.

It is another object of the present invention to disclose a device forand method of vertically adjusting parts in a parts bin where thelifting means is located externally to the platform.

The objects of the present invention are realized by disclosing a devicefor and method of vertically adjusting parts in a parts bins to a levelthat minimizes the bending and movement required by a human operator toremove a part from the parts bin. It is believed that injuries would beavoided by eliminating unnecessary bending of the lower back,eliminating unnecessary pulling on the shoulders, eliminatingunnecessary pulling on the upper back, and other similar movements.

The present invention discloses a device for and method of verticallyadjusting parts in a parts bin that includes a mechanism for acceptinginput from an operator that results in a vertical adjustment that isunder the control of the operator.

The present invention discloses a device for and method of verticallyadjusting parts in a parts bin that includes an electronic device thatvertically adjusts the parts in a parts bin without any input from anoperator.

The present invention discloses a device for and method of verticallyadjusting parts in a parts bin that utilizes either a mechanical, ahydraulic, and a pneumatic mechanism to vertically adjust the parts in aparts bin. Each of these means for lifting are either under the controlof the operator or is controlled electronically or automatically,without any input from an operator.

The present invention discloses a device for and method of verticallyadjusting parts in a parts bin that is portable or permanently mountedwithin the bin.

The lifting mechanism, and the electronic leveling device, whenutilized, can be made to fit any size parts bin and level any type ofpart.

The present invention discloses a device for and method of verticallyadjusting parts in a parts bin that is made of strong, lightweight,long-lasting, economic, and ergonomic materials such as polyethylenewhich will not rust, mildew or deteriorate, is easy to clean, and isimpervious to moisture oils, and most chemical agents.

The present invention discloses a device for and method of verticallyadjusting parts in a parts bin that uses a calibrated spring as alifting means. The spring is calibrated or chosen to correspond to theweight of parts stored in the parts bin. The spring constant of thespring (the spring constant is “k” in the equation F=kx, where “F”equals the force supplied by the spring and “x” equals a springdisplacement distance) is selected so that the weight of the partsremoved will cause the platform to move through a distance “x”. Thedistance “x” is also essentially equal to the height of parts beingremoved from the bin. The force (“F”) supplied by the spring causes theplatform to rise a height generally equal to the height of the partsremoved. Through this mechanism, the spring keeps the parts at theproper height, so that an operator does not have to provide any input tokeep the parts in the parts bin at the proper vertical adjustment.

Through the same mechanism, the ergonomic parts bin elevator of thepresent invention lowers the parts in the parts bins as additional partsare added to the parts bin in order to keep the parts in the parts binat a vertical position that minimizes the bending required to remove apart from the parts bin. As parts are removed from the parts bin, thepresent invention raises the level of the parts in the parts bin so thatthe parts remaining in the parts bin maintain the vertical position thatminimizes the bending required to remove a part from the parts bin.

The present invention can be made to be portable or stationary. It canbe designed to fit into any existing parts bin. It can be made tovertically adjust to any type of part.

The present invention discloses a method for emptying parts from aplatform truck. First parts are emptied from a parts containerpositioned on the platform of a platform truck. Next, the size of anopen storage space under the platform is increased. Finally, the partscontainer is stored in the open storage space.

The advantages and benefits of the present invention are that bending isminimized, and therefore, injuries due to bending are reduced. Damage toparts is reduced, since fewer parts will be dropped due to the lowerstrain associated with the minimized bending of the present invention.The present invention is easy to use, can be automatic, and requiresminimal maintenance.

Productivity is increased due to the reduced time and strain required tomove parts in and out of the parts bin, and costs and expenses areminimized, due to a reduction in parts damage.

Another advantage of the present invention is that the space under theplatform is usable for storage, dunnage or other purposes.

Still another advantage of the present invention is that the platformmoves smoothly along guide rods with no binding. The linear bearingsalso eliminate any tipping factor.

Another advantage of the present invention is that the ergonomicplatform truck may be positioned at a pitch angle with respect to avertical line while continuing to eliminate any tipping factor.

Another advantage of this invention is that a dual platform truck havinga pair of platform assemblies is provided.

Yet another advantage of this invention is that an ergonomic handtruckis provided having a platform assembly and being easily transported fromplace to place.

Another advantage of this invention is that the platform isself-aligning and thus able to easily compensate for possibleinconsistencies that may be caused by excessive forces or by material ormanufacturing inaccuracies in the fabrication of the ergonomic platformtruck.

Still other benefits and advantages of the invention will becomeapparent to those skilled in the art to which it pertains upon a readingand understanding of the following detailed specification.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention may take physical form in certain parts and arrangement ofparts, a preferred embodiment of which will be described in detail inthis specification and illustrated in the accompanying drawings, whichform a part hereof and herein:

FIG. 1 is a cut-away schematic front view of a first embodiment of thepresent invention.

FIG. 2 is a cut-away schematic front view of a second embodiment of thepresent invention.

FIG. 3 is a cut-away schematic front view of a third embodiment of thepresent invention.

FIG. 4 is a cut-away schematic front view of a fourth embodiment of thepresent invention.

FIG. 5 is a cut-away schematic front view of a fifth embodiment of thepresent invention.

FIG. 6 is a cut-away front view of a bin according to the presentinvention.

FIG. 7 is a cut-away top front view of the bin of FIG. 6 of the presentinvention.

FIG. 8 is a perspective front view of a sixth embodiment of the presentinvention shown holding parts.

FIG. 9 is a perspective side view of the sixth embodiment shown holdingparts.

FIG. 10 is a perspective front view of the sixth embodiment shownwithout parts.

FIG. 11 is a perspective side view of the sixth embodiment shown withoutparts.

FIG. 12 is a perspective side view of the sixth embodiment showing thesprings without spring covers.

FIG. 13 is a front view of an ergonomic platform truck when it is fullyloaded.

FIG. 14 is a front view of the ergonomic platform truck of FIG. 13showing how the open storage space can be used to store empty partscontainers.

FIG. 15 is a front view of an ergonomic platform truck which has astorage assembly mounted to the bin.

FIG. 16 is a front view of the ergonomic platform truck of FIG. 15showing how the storage assembly can be used to store empty partscontainers.

FIG. 17 is a side view of an ergonomic platform truck showing springslots and spring covers.

FIG. 18 is a side view of an ergonomic platform truck, which usesconical springs to lift the platform assembly.

FIG. 19 is a sectional view taken along the line 19—19 of FIG. 20showing the lip portion of the linear bearing.

FIG. 20 is an end view of the linear bearing used in this invention.

FIG. 21 is a side cut-a-way close-up view of a spring support bracketshowing spring slots.

FIG. 22 is a bottom cut-a-way view of a spring cover used in thisinvention.

FIG. 23 is a side cut-a-way view taken along the line 23—23 of FIG. 22.

FIG. 24 is an end view taken along the line 24—24 of FIG. 22 showing thechannel shape of the spring cover and the foam panel used to protect thesprings.

FIG. 25 is a side view of an ergonomic platform truck showing a door,which covers the springs.

FIG. 26 is a side view of the platform assembly used in this invention.

FIG. 27 is a perspective front view of an ergonomic platform truckhaving a bucket for use in holding loose parts.

FIG. 28 is side perspective view of another embodiment, a dual platformtruck having a pair of platform assemblies mounted to one frame.

FIG. 29 is an end view of the dual platform truck of FIG. 28 showing theguide rods positioned at a pitch angle with respect to a vertical line.

FIG. 30 is top partial perspective view of the dual platform truck ofFIG. 28 showing the first deck guide receiving the first guide rod.

FIG. 31 is an end partial perspective view of the dual platform truck ofFIG. 28 showing the third deck guide receiving the third guide rod andshowing the first platform assembly.

FIG. 32 is partial side perspective view of a dual platform truckshowing cam rollers rolling along the roller surfaces of a pair ofroller guides.

FIG. 33 is top partial view of the dual platform truck of FIG. 30showing the cam rollers received within channels.

FIG. 34 is a schematic view of a spring restraint cable with a pair ofstop sleeves and a secure plate.

FIG. 35 is a perspective view of another embodiment, an ergonomichandtruck.

FIG. 36 is a perspective view of the ergonomic handtruck of FIG. 35showing the optional features of a latch system and a first embodimentdamping means.

FIG. 37 is an exploded side view of a second embodiment damping meansincluding a pair of dampers.

FIG. 38 is a top view of the damping means of FIG. 37 showing how thedamper receives the support rod and how it attaches to the deck guide.

FIG. 39 is a top view of another platform truck embodiment, aself-aligning platform assembly.

FIG. 40 is a side view taken along the line 40—40 of FIG. 39.

FIG. 41 is a partial sectional view taken along the line A—A of FIG. 40showing the adjustment gap Z between the platform and the deck guide.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to the drawings wherein the showings are for purposes ofillustrating a preferred embodiment of the invention only and not forpurposes of limiting the same, the present invention is a device for andmethod of vertically adjusting parts in a parts bins to a level thatminimizes the bending required of a human operator to remove a partfrom, or add parts to, the parts bin. FIG. 1 is a cut-away view of afirst embodiment 10 of the present invention.

The first embodiment 10 of the present invention includes a parts bin 12for holding parts (not shown) on a platform 16 for defining the lowestvertical position that a part can take in the parts bin 12, and alifting mechanism 18 for vertically adjusting the platform 16 so thatthe parts in the parts bin 12 are always at a vertical position thatminimizes the bending required of an operator to remove parts from, oradd parts to, the parts bin 12. Platform 16 may be a container, which isattached to the planar platform 16 or upper panel 22. Platform 16 can bepermanently or removably attached to upper panel 22.

The lifting mechanism 18 for lifting the platform 16 can be realized inany one of a number of ways. One possible realization is a scissor-typejack 26 as depicted in FIG. 1. The scissor-type jack 26 shown in FIG. 1has a crank 30 extending through an opening 32 in the parts bin 12. Thecrank 30 enables an operator to vertically adjust the level of the partsto a level that minimizes the bending required of an operator to removeparts from, or add parts to, the parts bin 12. The scissor-type jack 26of FIG. 1 includes a pedestal 36, a first support member 40, a secondsupport member 42, a third support member 44, a fourth support member46, planar platform 16, a threaded bar 50, and a crank 30.

The first support member 40 and the second support member 42 arepivotally joined to the pedestal 36 at a first end 54, 56 respectively.A second end 60 of the first support member 40 and second end 62 of thesecond support member 42 each have a threaded hole (not shown). Thethreaded hole of the first support member 40 faces the threaded hole ofthe second support member 42 so that the threaded bar 50 can travelthrough these holes to adjust the distance between the first supportmember 40 and the second support member 42 and, therefore, the verticalposition of the platform 16. The crank 30 is connected to a first end 66of the threaded bar 50 and is used to adjust the distance between thefirst support member 40 and the second support member 42. The thirdsupport member 44 and the fourth support member 46 are pivotally joinedto the upper panel 22 at their first ends 72,74, respectively. Thesecond end 76 of the third support member 44 and the second end 78 ofthe fourth support member 46 each have a threaded hole (not shown). Thethreaded hole of the third support member 44 faces the threaded hole ofthe fourth support member 46. The threaded hole end of the third supportmember 44 is pivotally joined to the threaded-hole end of the firstsupport member 40 so that the threaded bar 50 can travel through theseholes and adjust the vertical position of the upper panel 22 and,therefore, the platform 16. The threaded-hole end of the fourth supportmember 46 is pivotally joined to the threaded-hole end of the secondsupport member 42 so that the threaded bar 50 can travel through theseholes and adjust the vertical position of the upper panel 22 and,therefore, the platform 16. Vertically adjusting the upper panel 22 viathe crank 30 results in the vertical adjustment of the platform 16 andthe parts.

FIG. 2 depicts a second embodiment 80 of the present invention that is,essentially, the same as the device of FIG. 1 with the addition ofelectronics to automatically adjust the vertical position of the parts.In FIG. 2, the lifting mechanism 18 (e.g., a scissor-type jack) forvertically adjusting the parts, is fully contained within the parts bin12. A motor 84 automatically turns the crank 30 of the scissor-type jack26 in order to raise, or lower, the lifting mechanism 18. Alight-emitting diode (LED) 88 is attached to the inside top of one ofthe walls of the parts bin 12. A photo-detector 92 is attached to theinside top wall of the parts bin 12 that is directly across from, and inthe light path of, the light-emitting diode 88. The light-emitting diode88 and the photo-detector 92 are electrically connected to the motor 84so that the motor 84 will turn the crank 30 and vertically adjust theplatform 16 and the parts, so that the light beam from thelight-emitting diode 88 is just barely interrupted. Electronics (notshown) are contained within the motor 84 that turns the crank 30 so thatthe platform 16 is vertically adjusted to the point where the light beamfrom the light-emitting diode 88 is just interrupted. The electronics inthe motor 84 will periodically raise, and lower, the platform 16 inorder to check the position of the platform 16 to maintain the verticalposition of the parts to a level that just barely interrupts the lightfrom the light-emitting diode 88. This ensures that the verticalposition of the platform 16 is lowered whenever parts are added to it.When parts are removed, the light from the light-emitting diode 88 is nolonger interrupted. Photo-detector 92 then detects light emitted fromthe light-emitting diode 88 and signals the motor 84 to turn the crank30 in order to raise the platform 16 and parts positioned thereon, sothat the light from the light-emitting diode 88 is interrupted onceagain. This ensures that the parts in the parts bin 12 are always at thevertical position that minimizes the bending required of an operator toremove a part from, or add a part to, the parts bin 12.

FIG. 3 depicts the third embodiment 100 of the present invention thatis, essentially, the same as the device of FIG. 1 with a different typeof lifting mechanism (shown as 18 in FIG. 1). In FIG. 3, the liftingmechanism 18 can be either a hydraulic cylinder or a pneumatic cylinder.As in FIG. 1, the lifting mechanism 18 of FIG. 3 extends outside of theparts bin 12 so that an operator can provide an input via a controldevice 102 (e.g., a switch) to control the vertical position of theplatform 16 and, therefore, the vertical position of the parts in theparts bin 12.

FIG. 4 depicts a fourth embodiment 110 of the present invention that is,essentially, the same as the device of FIG. 3 with the addition ofelectronics to automatically adjust the vertical position of the partsin the parts bin 12. In FIG. 4, the lifting mechanism 18 (i.e., either ahydraulic cylinder or a pneumatic cylinder) is fully contained withinthe parts bin 12. A motor 114 is added that automatically adjusts thevertical position of the lifting mechanism 18. A light-emitting diode118 is attached to the inside top of one of the walls of the parts bin12. A photo-detector 122 is attached to the inside top wall of the partsbin 12 that is directly across from, and in the light path of, thelight-emitting diode 118. The light-emitting diode 118 and thephoto-detector 122 are connected to the motor 114 so that the motor 114will raise, or lower, the lifting mechanism 18 and, therefore,vertically adjust the platform 16 and the parts enough to just barelyinterrupt the light beam from the light-emitting diode 118 to thephoto-detector 122. Electronics (not shown) are contained within themotor 114 to adjust the vertical position of the lifting mechanism 18 sothat the platform 16 is vertically adjusted to the point where the lightbeam from the light-emitting diode 118 is just interrupted. Theelectronics in the motor 114 will periodically raise, and lower, theplatform 16 in order to check the position of the parts. This ensuresthat the vertical position of the platform 16 is lowered whenever partsare added to the parts bin 12. When parts are removed from the parts bin12, the light from the light-emitting diode 118 will no longer beinterrupted and the photo-detector 122 will detect light emitted fromthe light-emitting diode 118 and signal the motor 114 to verticallyadjust the lifting mechanism 18 in order to raise the platform 16 andparts positioned thereon, so that the light from the light-emittingdiode 118 is interrupted once again. This ensures that the parts arealways at the vertical position that minimizes the bending required ofan operator to remove a part from, or add a part to, the parts bin 12.

FIGS. 5-7 show a fifth embodiment 130 of the present invention. Thefifth embodiment 130 is, essentially, the same as the devices of FIGS. 2and 4 with a different type of lifting mechanism. The lifting mechanism26 of FIGS. 5-7 is a calibrated spring 134. The spring 134 must becalibrated for the type of part placed on platform 16 of the parts bin12, so that the vertical position of the parts is always at the verticalposition that minimizes the bending required of an operator whenremoving parts from, or adding parts to, the parts bin 12.

In a sixth embodiment of this invention, FIGS. 8-12 show an ergonomicplatform truck 170 which has a bin 180 and a platform assembly 280 whichincludes platform 200. The bin 180, in this embodiment, is a box shownbest in FIG. 8, with a base 181, a top 182 and a front 183. The top 182,in this embodiment, is formed of three cross members 198, 199, 203. Boththe top and front 182, 183 are open. By open it is meant that there isno portion of the ergonomic platform truck 170 which would impede theplacement or removal of parts 172 from the top or front 182, 183.Rigidly attached to the base 181 and shown best in FIGS. 8-9, is sideframing 269 and four columns, 184, 185, 186, 187 which are verticallydisposed. The ergonomic platform trucks 170 of this invention arestackable. By stackable it is meant that platform trucks, which couldinclude any number of ergonomic platform trucks 170, can be stacked ontop of each other for storage or other purposes. In this embodimentstacking pins 188 are used but it should be noted that any means chosenwith sound engineering judgement such as equipping the four columns 184,185, 186, 187 with joinable angle iron could also be used. The stackingpins 188 are mounted to the top while stacking slots 189 are formed inthe bottom of each column 184, 185, 186, 187. The stacking slots 189 aremade to receive the stacking pins (similar to 188) of another associatedplatform truck (not shown).

With reference to FIGS. 8-11, forklift brackets 190 for receiving theforks of an associated forklift (not shown) are rigidly attached to thebase 181. Also attached to the base 181 are casters. In this preferredembodiment, two casters 191 are swivelly mounted and two other casters192 are rigidly mounted to the base 181 via caster mounting plates 193.Guide rods 194, 195, 196, 197 are vertically disposed on the bin 180 forreasons, which will be explained below.

With reference now to FIGS. 10-11, 19-20, 26, platform assembly 280 isvertically moveable within the bin 180 and includes platform 200 whichis generally horizontal and planar and is constructed so as to holdparts thereon, such as parts 172 (shown in FIGS. 8-9). It should benoted that the parts can be of any type used with sound engineeringjudgement. The platform assembly 280 has first and second sides 201, 202having first and second spring support brackets 208, 209 respectively.The purpose of the spring support brackets 208, 209 will be explainedbelow. The platform assembly 280 also has, as best seen in FIG. 11, deckguides 204, 205, 206, 207, which are vertically disposed. Within eachdeck guide 204, 205, 206, 207, at the top and bottom is a linear bearing242. In this preferred embodiment each linear bearing 242 has a firstend 250 with a lip portion 252 and a second end 251. Lip portions 252remain external to deck guides 204, 205, 206, 207, while second ends 251are received within deck guides 204, 205, 206, 207. The linear bearings242 and thus the deck guides 204, 205, 206, 207 receive and arevertically moveable along the guide rods 194, 195, 196, 197respectively. The linear bearings 242 assure that the platform assembly280 moves smoothly along guide rods 194, 195, 196, 197 with no binding.The linear bearings 242 also eliminate any tipping factor. The deckguides 204, 205, are rigidly attached to the first side 201 of theplatform assembly 280 while deck guides 206, 207 are likewise rigidlyattached to the second side 202. Second spring support bracket 209 hasfirst and second ends 274, 275 rigidly connected to deck guides 207, 206respectively. First spring support bracket 208 is similarly rigidlyconnected to deck guides 204, 205. All rigid connections in thisembodiment are welds but other connecting means chosen with soundengineering judgment would also be acceptable for this invention. Thoughthe platform 200 can be customized to any required dimensions, it hasbeen learned that to minimize the stress put on an operators back whenlifting parts (172 in FIGS. 8-9), it is best to maintain the width W1 ofthe platform 200 under 30 inches (76.2 centimeters).

With reference now to FIG. 8-9, 13-14 and 27, parts may be held on theplatform 200 in various ways. As seen in FIGS. 8 and 9, sometimes theparts, such as parts 172, are sized and shaped such that they willremain on the platform 200 with no additional containing means. Othertimes, as seen in FIGS. 13 and 14, the parts are placed insidecontainers, such as laden containers 176. It may also be desirable tohold loose parts that are not sized or shaped to remain on the platform200 without using containers. Thus, as seen in FIG. 27, the ergonomicplatform truck 170 may be equipped with a bucket 300. The bucket 300 isideal for use with parts that are spherical in shape such as golf balls(not shown). Of course the bucket 300 could be used with any partschosen with sound engineering judgement. The bucket 300 is verticallydisposed around the perimeter of the platform 200 and preferablyincludes first, second, third and fourth walls 302, 304, 306, 308. Inthis preferred embodiment first wall 302 is rigidly connected to thefront 183 of the bin 180. Thus, in this case, the front 183 of the bin180 is not open. Second, third and fourth walls 304, 306, 308, arerigidly connected to the left side 312 and right and back sides (notshown) of the platform 200. When the platform 200 is at it lowest point(not shown) the bucket 300 forms a box having a bottom (platform 200),four sides (first, second, third and fourth walls 302, 304, 306, 308)and a top 301 that is open. As the platform 200 is raised, the front 303of the bucket 300 gradually opens. When the platform 200 reaches itsmaximum height, as shown in FIG. 27, the front 303 of the bucket 300 iscompletely open. Thus, the front 303 of bucket 300 is selectively openor closed depending on the vertical position of platform 200.

With reference now to FIGS. 12-14, springs 211, 214, 217, 220, 223, 226,229, 232 are used to lift platform assembly 280 within the bin 180.Springs 211, 214, 217, 220, 223, 226, 229, 232 are disposed to the sideof and externally to the platform 200 so that they are not positionedeither directly above or directly below the platform 200. For thisreason, there is an open storage space 174 below the platform 200, whichincludes the entire space between the platform 200 and the base 181. Theopen storage space 174 could be used for storage or other uses. Oneefficient use of the open storage space 174 is for dunnage such as emptyparts containers. In a typical application, shown in FIG. 13, theergonomic platform truck 170 would come to the operator full of ladencontainers 176, which contain parts to be used, by the operator. Theweight of the parts in the laden containers 176 hold the platform 200 ata level which is a distance X1 from the top of the ergonomic platformtruck 170 so that the top most laden containers 176 are at the preferredheight for the operator. As the laden containers 176 are emptied oftheir parts and removed, the weight on the platform 200 is lessened andthe springs 211, 214, 217, 220, 223, 226, 229, 232 raise platform 200 sothat it maintains the preferred height for the operator. As the platform200 raises, open storage space 174 grows larger. Thus, it can be easilyunderstood that open storage space 174 is an ideal place to storeemptied containers 177 because just as emptied containers 177 becomeavailable, additional open storage space 174 also becomes available.FIG. 14 shows the ergonomic platform truck 170 holding laden containers176 on its platform 200 and holding emptied containers 177 in its openstorage space 174. It should be noted that the platform 200 is now at adistance X2 (where X2 is significantly smaller than X1) from the top ofthe ergonomic platform truck 170 so that the laden containers 176continue to be at the preferred height for the operator.

With reference to FIGS. 15-16, another way to store emptied containers177 is by mounting a storage assembly 178 to the side of the ergonomicplatform truck 210 thus providing an open storage space 179. Thisstorage assembly 178 can be made in any manner and of any materialchosen with sound engineering judgement but in this embodiment it ismade of steel members 175 fixedly attached to the bin 286. Of course astorage assembly 178 could just as easily be mounted to the other side,both sides, or the back of the ergonomic platform truck 210 as well.FIG. 16 shows the ergonomic platform truck 210 holding laden containers176 on its platform 200 and holding emptied containers 177 in its openstorage space 179. It may also be desirable to cover the storageassembly 178 with a cover 239 as shown in FIG. 15.

With reference now to FIGS. 12, 17, 21, 26, springs 223, 226, 229, 232have second ends 225, 228, 231, 234 respectively, operatively connectedto the second spring support bracket 209 and first ends 224, 227, 230,233 respectively, operatively connected to the cross member 203 directlyabove the second spring support bracket 209. The connection to thesecond spring support bracket 209 and the cross member 203 can be of anytype chosen with sound engineering judgement but in this embodiment isby means of holes 237, 238 respectively. Similarly, springs 211, 214,217, 220 have second ends 213, 216 (second ends of springs 217, 220 notvisible) respectively, operatively connected to the first spring supportbracket 208 and first ends 212, 215, 218, 221 respectively, operativelyconnected to the cross member 198 directly above the first springsupport bracket 208. FIG. 17 shows another but similar embodimentwherein the ergonomic platform truck 171 has springs 173 which areconnected to cross member 235 and spring support bracket 236 by means ofspring slots 285. The spring slots 285 are best seen in FIG. 21. Whetherconnected by holes 237, 238, by spring slots 285, or by other means, itis desirable to be able to selectively connect and disconnect individualsprings 223, 226, 229, 232 or 173. In this way the overall springstrength can be adjusted to suit the need, i.e., to suit the weight ofthe parts to be placed on ergonomic platform truck 170 or 171. Anefficient way to disengage a spring is to disconnect the second end 225of spring 223, for example, from the second spring support bracket 209while allowing the first end 224 to remain connected to cross member203. In this way the spring 223 remains in place and can be reconnectedto the second spring support bracket 209 when ever it is desirable toincrease the overall spring strength.

With reference again to FIG. 12, springs 211, 214, 217, 220 aresimilarly operatively connected to the first spring support bracket 208and the cross member 198 directly above the first spring support bracket208. The springs 211, 214, 217, 220, 223, 226, 229, 232 which providelifting means for the platform 200 so that it can move vertically alongthe guide rods 194, 195, 196, 197, can be of any type chosen with soundengineering judgement but in this embodiment are extension springshaving spring constants chosen and matched to the weight of the parts172 (shown in FIGS. 8 and 9). It should be noted that while eightsprings were used in this embodiment, the exact number can and should bemodified to best suit the engineering requirement.

With reference now to FIGS. 10-11, 17, 22-24, each spring (shown as 211,214, 217, 220, 223, 226, 229, 232 in FIG. 12) is individually covered onthe inside and on the outside by spring covers 241. In this embodimentspring covers 241 are channel-shaped and have openings 246 wherebyscrews (not shown) are used to attach the spring covers to the bin 180.Of course other shapes and attaching means chosen with sound engineeringjudgement are also possible. It may also be desirable, as shown in FIG.24, to use spring protecting means such as foam panels 254 to protectthe springs. It should be noted that the panels 254 not only protect thesprings but they also provide sound protection means whereby the soundgenerated by the springs as they are extended and contracted is absorbedand therefore largely dissipated before it reaches the ears of anynearby person. In the preferred embodiment the panels 254 are formed offoam for sound protection purposes. However, the panels can be formed ofany sound absorbing material chosen with sound engineering judgment. Thespring covers 241 do not fully surround the springs (shown as 211, 214,217, 220, 223, 226, 229, 232 in FIG. 12) because first and second springsupport brackets 208, 209 move between them as the platform assembly 280is moved vertically. In an alternate embodiment, shown in FIG. 17, allthe springs 173 on one side of ergonomic platform truck 171 are jointlycovered on the inside and on the outside by spring covers 240. Onceagain it may be desirable to use spring protecting means such as foampanels 257 positioned within spring covers 240 to protect the springs173 and to provide sound protection means. In an alternate design, shownin FIG. 25, an ergonomic platform truck 260 may utilize a door 262 thatswings on a hinge 264 and performs the duty of a spring cover. Doors 262make springs 266 very accessible for adjustment or maintenance.

With reference now to FIG. 18, an ergonomic platform truck 243 is shownhaving conical springs 244 to lift platform assembly 280. The conicalsprings 244 are operatively connected at one end to the bottom ofplatform 200 within upper clam shells 270 and at the other end to thebase 181 within lower clam shells 271. The conical springs 244, whichprovide lifting means for the platform assembly 280 so that it can movevertically along the guide rods 245, can be of any type commerciallyavailable chosen with sound engineering judgment having spring constantsmatched to the weight of the parts. It should be noted that while twosprings were used in this embodiment, the exact number can and should bemodified to best suit the engineering requirement.

All of the embodiments of the present invention can be stationary orportable. All of the embodiments of the present invention can beconstructed to fit any size parts bin 12, or can be a stand-alone unit,and vertically adjust to any type (e.g., size, weight, etc.) of part.

The materials used to construct the present invention may be strong,lightweight, long lasting, economic, and ergonomic. For example,polyethylene (which will not rust, mildew or deteriorate, is easy toclean, and is impervious to moisture, oils, and most chemical agents)may be used.

With reference now to FIGS. 28-31, in another embodiment, a dualplatform truck 400 is shown. In FIGS. 28-29 it is shown holdingassociated items 424 that can be of any type chosen with soundengineering judgment. The dual platform truck 400 includes a frameassembly 404 having first and second sides 406, 408 and first and secondends 410, 412. Preferably, at least at each quadrant the frame assembly404 also includes first and second segments 414, 416. In the embodimentshown, each side of the frame assembly has first and second segments414, 416 that extend from the first end 410 to the second end 412. Thefirst and second segments 414, 416 may form the top and bottom 418, 420respectively of the frame assembly 404 as shown or alternatively, thefirst and second segments 414, 416 may be positioned at any locationchosen with sound engineering judgement. Thus, it should be clear thatthe segments 414, 416 may be position between the top and bottom 418,420 of the frame assembly 404.

With reference now to FIGS. 28 and 30, a first guide rod 430 has a firstend 432 operatively connected to the first segment 414 on the first end410 of the first side 406 of the frame assembly 404 and a second end 434operatively connected to the second segment 416 on the first end 410 ofthe first side 406 of the frame assembly 404. Preferably, the guide rod430 is fixedly connected to the segments 414, 416. Second, third andfourth guide rods 440, 450, 460 are similarly positioned on the firstend 410 second side 408, second end 412 first side 406 and second end412 second side 408 respectively.

With reference to FIGS. 28-31, the dual platform truck 400 includesfirst and second platform assemblies 470, 500 each preferably includinga cantilevered platform. It should be noted, however, that only a singleplatform assembly is required and would be similar to the platform truck170 shown in FIGS. 8-12 and discussed above. The first platform assembly470 is selectively movable along the first guide rod 430 and includes afirst deck guide 472 that receives the first guide rod 430 and a firstplatform 474 that is preferably fixed to the first deck guide 472. Theplatform 474 may be continuously planer in shape (as is the platform 200shown in FIG. 10) or may consist of generally planar but with openingsas shown in FIG. 31. In either case, the platform 474 is constructed soas to hold items (shown as 424) thereon. These items can be of any typechosen with sound engineering judgment.

Still referring to FIGS. 28-31, within the first deck guide 472 at leasta first linear bearing (not visible) is positioned and receives thefirst guide rod 430. The linear bearing 478 is preferably similar to thelinear bearing 242 described above. Most preferably, two linear bearingsare positioned within the deck guide 472, at the top and bottom of thedeck guide 472. A first spring bracket 480 is fixedly connected to thefirst deck guide 472 for purposes to be discussed below. A first spring482 is used to lift the first platform assembly 470 along the firstguide rod 430. The first spring 482 has a first end 484 that isoperatively connected to the first segment 414 and a second end 486 thatis operatively connected to the first spring support bracket 480 asshown. Of course additional springs may be used as shown to provide therequired spring strength for the platform truck 400.

Still referring to FIGS. 28-31, the second platform assembly 500includes a second deck guide (not visible but similar in construction tothe first deck guide 472 and third deck guide 520) and a second platform504 and is constructed similar to the first platform assembly 470. Asecond spring 506 is used to selectively lift the second platformassembly 500 along the second guide rod 440. It should be noted that asingle guide rod may be sufficient for each platform assembly. Thesingle guide rod may be positioned on the frame assembly 404 half waybetween the ends of the platform, for example. In the embodiment shown,however, each platform assembly uses two guide rods. Thus, the thirdguide rod 450 is positioned opposite the first guide rod 430 on thesecond end 412, first side 406 of the frame assembly 404. A third deckguide 520 is similar in construction to the first deck guide 472 and isalso fixedly connected to the first platform 474. A third spring 522assists the first spring 482 in lifting the first platform assembly 470.(As noted above, additional springs as shown can also be used.)Similarly, the fourth guide rod 460 is positioned opposite the secondguide rod 440 on the second end 412, second side 408 of the frameassembly 404. A fourth deck (not visible but similar in construction tothe first deck guide 472 and third deck guide 520); a similar inconstruction to the second deck guide 502 and is also fixedly connectedto the second platform 504. A fourth spring 532 assists the secondspring 506 in lifting the second platform assembly 500. Again,additional springs may also be used.

With reference now to FIGS. 28 and 32-33, when very heavy loads areplaced on the cantilevered platform assemblies 470, 500 the guide rods430, 440, 450, 460 may be exposed to excessive bending loads that tendto bow them. To counteract this bending load additional guide rods couldbe added to the platform assembly. However, a lighter and less expensivemethod to counteract this bending load is to use cam followers as willnow be described. A roller guide 540 is positioned on the frame assembly404 preferably near each guide rod. Thus, four roller guides 540 areshown. Each roller guide 540 includes a roller surface 542. A cam roller546 is rotatably connected to each deck guide 430, 440, 450, 460. A camextension bracket 548, for example, may extend from each deck guideabout which each cam roller 546 may selectively rotate. It should benoted that the extension bracket 548 preferably includes a slot 550through which the cam roller 546 is attached. This slot 550 providesadjustment so that the cam roller 546 can be properly position relativeto the roller guide 540. Thus, as the platform assemblies 470, 500 aremoved along their guide rods, the cam rollers 546 roll along the rollersurfaces 542 of the roller guides 540. In this way, the bending load isdistributed not only through the linear bearings 478 within the deckguides 472 but also through the cam rollers 546 to the roller guides540. If the bending load is great, each deck guide 472 may have two camrollers 546, preferably at opposite ends of the deck guide 472, to helpin distributing the bending load to the roller guide 540. In this case,as shown, each cam roller 546 attached to a single deck guide 472preferably contacts the roller surface 542 of the same roller guide 540.Preferably, while the platform 474 extends from the first deck guide 472generally in a first direction 490, the roller surface 542 facesgenerally in a second direction 492 that is substantially opposite tosaid first direction 490.

With continuing reference to FIGS. 28 and 32-33, to again assist indistributing loads, it may be desirable to form an alternate rollerguide 552 that has a channel 554 defining first and second rollersurfaces 556, 558 therewithin. In this case, as the platform assembly470 is moved along the guide rods 430, 450, the cam roller 546 rollsalong the first or second roller surface 556, 558 depending on theparticular load applied to the platform 474.

With reference now to FIG. 28 and 29, it should be noted that either orboth platform assemblies 470, 500 may be positioned at a pitch anglewith respect to a vertical line VL. As shown, the first and third guiderods 430, 450 are substantially parallel and are positioned at a firstpitch angle PA1 with respect to the vertical line VL. Similarly, thesecond and fourth guide rods 440, 460 are substantially parallel and arepositioned at a second pitch angle PA2 with respect to the vertical lineVL. The particular degree of angle for the first and second pitch anglesPA1, PA2 can be any chosen with sound engineering judgement but are atleast 1°, about 5° as shown.

FIGS. 28, 30-31 and 34 show an optional feature, spring restraint means562 for use in restraining the springs should a spring break during theoperation of the platform truck 400. In the preferred embodiment, thespring restraint means 562 is a spring restraint cable 564. As shown, aseparate spring restraint cable is received within each spring andincludes a first end 566 operatively connected to the first segment 414and a second end 568 operatively connected to the second segment 416.Although the cables 564 may be attached to the platform truck 400 in anymanner chosen with sound engineering judgement, in the preferredembodiment shown, stop sleeves 570 are used. In particular, a first stopsleeve 570 is first connected to a first end of the cable 564. Thesecond end of the cable 564 is then fed through an opening (not visible)in the first segment 414 and through the spring (first spring 482, forexample). Next, a second stop sleeve 570 is connected to the second endof the cable 564. Then, the second stop sleeve 570 is fed through anopening (not visible) in the second segment 416. Finally, a secure plate572 is placed between the second stop sleeve 570 and the bottom surfaceof the second segment 416. It should be noted that the first stop sleeve570 is larger than the opening in the first segment 414 but that thesecond stop sleeve 570 is smaller than the opening in the second segment416. It should also be noted that the length L of the restraint cable564 is sufficient to extend from the first segment 414 through thesecond segment 416. In operation, should a spring break, it will be heldlargely in place by the cable 564 and therefore be prevented fromtraveling beyond the platform truck 400.

With reference now to FIG. 35, in another embodiment, a handtruck 600 isshown. The handtruck 600 has a frame assembly 602 including top andbottom portions 604, 606. A handle 608 extends from the frame assembly602 for use by an operator in transporting the handtruck 600. A pair ofwheels 610 are rotatably connected to the bottom portion 606 of theframe 602. The wheels 610 have two primary functions. One function isfor use in transporting the handtruck 600 from one place to another. Thesecond function is for pivoting the handtruck 600 about the wheels 610.This is a normal operating procedure for handtrucks and enables theoperator to adjust the handtruck from a rest position to a transportposition as is well known in the handtruck art. It should be noted thatadditional frame members (not shown) could be added to the handtruck 600to prevent the item being transported (not shown) from inadvertentlycontacting the later to be described platform assembly.

With continuing reference to FIG. 35, the handtruck 600 has a pair ofguide rods 612 each having first ends 614 operatively connected to afirst segment 616 of the frame assembly 602 and second ends 618operatively connected to a second segment 620 of the frame assembly 602.Although at least two guide rods 612 are preferred this invention willalso work well with a single guide rod 612. The handtruck 600 alsoincludes a platform assembly 630 that is moveable along the guide rods612. The platform assembly 630 includes a pair of deck guides 632 thatreceive the guide rods 612 and a platform 634 that is connected,preferably fixedly, to the deck guides 632. The platform 634 isconstructed to hold any type of item chosen with sound engineeringjudgement such as beverage containers and household goods.

With continuing reference to FIG. 35, within each deck guide 632 atleast a first linear bearing (not visible) is positioned and receivesthe corresponding guide rod 612. The linear bearing is preferablysimilar to the linear bearing 242 described above. Most preferably, twolinear bearings are positioned within each deck guide 632, at the topand bottom of the deck guide 632. A spring support bracket 638 isconnected to the deck guides 632 for purposes to be discussed below.Although a single spring works well with this invention, a pair ofsprings 640 are shown and are used to lift the platform assembly 630along the guide rods 612. Each spring 640 has a first end operativelyconnected to the first segment 616 and a second end operativelyconnected to the spring support bracket 638 as shown. Of courseadditional springs may be used to provide the required spring strengthfor the platform assembly 630. It should be noted that the guide rods612 could be positioned at opposite ends of the platform 634 instead ofon one side as shown. Similarly, the springs 640 could be positioned atopposite ends of the platform 634. In this way, the platform assembly630 would not be cantilevered, as shown, but would be side supportedsimilar to the platform assembly 280 shown in FIG. 10.

With reference now to FIG. 36, the handtruck 600 is shown having twooptional features, a latch system 700 and damping means 750. It shouldbe noted that both the latch system 700 and the damping means 750 couldalso be used with the platform trucks discussed above. The latch system700 can be used to prevent the platform 634 from raising under the liftforce of the springs 640. This feature is especially useful in caseswhere the handtruck 600 is being used to carry (and lift) items that mayinadvertently be removed (or lost) from the platform 634. The latchsystem 700 can be of any type chosen with sound engineering judgementthat permits the operator to selectively lock the latch system 700thereby selectively preventing the lift force of the springs 640 fromoperating or to selectively unlock the latch system 700 therebyselectively permitting the lift force of the springs 640 to operate onthe platform assembly 630. The latch system 700 shown includes a recoilunit 702, a connection member 704 and locking means 706 for selectivelylocking and unlocking the latch system 700. The latch system 700 maywork similar to the belt restraint mechanism in automobile seat beltsystems as will be discussed further below. The recoil unit 702 issupported by the frame assembly 602 such as by the second segment 620 asshown. The connection member 704 has one end attached to the platformassembly 630 such as to the spring support bracket 638 as shown andanother end that is connected within the recoil unit 702 where theconnection member 704 can be coiled (i.e., wrapped) within the recoilunit 702. The locking means 706 provides a convenient way for theoperator to lock and unlock the recoil unit 702. Preferably the lockingmeans 706 includes a foot pedal 708 that is operatively connected to therecoil unit 702 as shown. Other types of locking means are alsocontemplated, a hand lever, for example, may also be used.

With continuing reference to FIG. 36, the operation of the latch system700 will now be discussed. The latch system 700, when unlocked, permitsthe connection member 704 to freely extend from or coil within therecoil unit 702. When locked, however, the recoil unit 702 prevents theconnection member 704 (and thus the platform assembly 630) from movingupward. Thus, when the latch system 700 is unlocked (by pressing thepedal 708 if required), the operator may unload items from the platform634 allowing the platform assembly 630 to move upward under the liftforce of the springs 640. In this condition the connection member 704freely extends from the recoil unit 702 as the platform assembly 630 islifted. The operator may also load items onto the platform 634 causingthe platform assembly 630 to move downward and to overcome the liftforce of the springs 640. In this condition the connection member 704freely recoils within the recoil unit 702. When, on the other hand, thelatch system 700 is locked (by pressing the pedal 708 again), theconnection member 704 is locked in place (i.e., it is unable to extendfurther from the recoil unit 704) and the platform assembly 630 isunable to be lifted further. Thus, should an item inadvertently fall orbe knocked off the platform 634, the platform assembly will be preventedfrom raising. This is the condition most useful when the item loadedonto the handtruck 600 (as well as the handtruck 600) is beingtransported. Once the handtruck 600 is moved to the location where theitems to be loaded or unloaded reside, the operator can unlock the latchsystem 700 permitting the springs 640 to assist the operator bymaintaining the items at the desired height for loading and unloading asdiscussed above.

Still referring to FIG. 36, the damping means 750 may be used to damp orslow the spring force exerted by the springs 640. This may be required,for example, when the item being carried by the handtruck 600 is to beunloaded in one step. Preferably adjustment means 752 is also providedwhereby the degree of damping provided can be adjusted by the operator.The device used to provide the damping means 750 can be of any typechosen with sound engineering judgement. A first embodiment 750 a, shownin FIG. 36, includes a hydraulic cylinder 754 with an extension rod 756extending therefrom. The cylinder 754 may be supported by the frameassembly 602 such as by the first segment 616 as shown. The extensionrod 756 has one end attached to the platform assembly 630 such as to thespring support bracket 638 as shown. The adjustment means 752 mayinclude an adjustment screw 758 connected to the hydraulic cylinder 754whereby the amount of hydraulic fluid flow within the cylinder 754 iscontrolled. This in turn, controls the degree of damping provided by thehydraulic cylinder 754. In operation, the operator first sets theadjustment means 752 to the desired degree of damping. The operator thenunloads an item(s) as discussed above. The platform 634 will then raiseunder the lift force of the springs 640 but the speed of raising will beslowed (damped) due to the damping means 750. If the speed of raising isfaster or slower than desired, the operator can adjust the degree ofdamping by re-setting the adjustment means 752 accordingly.

FIGS. 37-38 show a second embodiment 750 b of damping means 750 to dampor slow the spring force exerted by the springs (not shown). Again itshould be noted that this damping means 750 may be used with any of theergonomic platform trucks discussed above. A support rod 774 is securedto the frame assembly (not shown) such as to the first and secondsegments 616, 620 shown in FIG. 36. The support rod 774 may bealternatively secured to the frame assembly. As shown in FIG. 37, a pairof dampers 770 are generally U-shaped and have first ends 771 that arepivotably attached to the deck guide 772 and second ends 773 thatreceive the support rod 774. Biasing means 775, such as spring 776,operatively biases the dampers 770 toward each other and against thesupport rod 774. For each damper 770, the first end 771 preferably formsa yoke portion 777 (seen best in FIG. 38) that attaches to oppositesides of the deck guide 772 and may be pivotably attached with a bolt778. The second end 773 preferably forms a groove 779 having a surface780 (shown in FIG. 38) that receives and contacts the support rod 774.The dampers 770 are formed of a material such as nylon that increases infriction force as the relative speed of the dampers 770 increases withrespect to the support rod 774 (preferably formed of steel). Inoperation, as the deck guide 772 moves at ordinary operating speeds(relatively slowly) in either upward or downward directions 781, 782,the frictional force applied to the deck guide 772 through the contactof the dampers 770 to the support rod 774 is minor permitting the deckguide 772 to move freely. Should the deck guide 772 begin moving upward781 at a faster speed however, such as if at item inadvertently fell offthe platform (not shown), the spring 776 and frictional force created bythe contact of the dampers 770 to the support rod 774 greatly increasesthereby slowing (damping) the spring force exerted by the lift springs(not shown) and thus slowing (damping) the speed of the raising deckguide 772.

With reference now to FIGS. 39-41, in another embodiment, aself-aligning platform system 800 is shown. The self-aligning platformsystem 800 includes a platform 802 and platform self-aligning means 804for automatically aligning the platform 802 with respect to the deckguides 806 and thus with respect to the frame assembly (not shown) ofthe platform truck. The self-aligning platform system 800 was inventedto compensate for possible inconsistencies in the platform truck. Theseinconsistencies may be caused by inaccuracies in the material ormanufacturing in the fabrication of the ergonomic platform truck. Themetal used in manufacture, for example, may vary in size and may developdimensional variations due to the heat from welding or othermanufacturing techniques. It is also possible that the components may befabricated “out of square” or that the manufacturer may make ameasurement mistake. Inconsistencies to the platform truck may also becaused by forces exerted on the truck. The truck may collide with a wallor column, for example, or may be struck by another truck. These forcesmay cause misalignment problems for the platform truck components. Theself-aligning platform system 800 makes all such possibleinconsistencies non-destructive to the operation of the platform truck.In particular, as the platform 802 is lowered or raised, if the platformtruck bows or if the frame is out of square, the platform 802 willautomatically adjust (i.e., move) to relieve any tension or bindingcreated thereby. Thus, the platform 802 is free to move and align itselfthereby compensating for all such inconsistencies and inaccuracies. Theself-aligning platform system 802 also enhances the non-bindingperformance provided by the deck guides 806 with linear bearings 808 asdescribed above. It should also be noted that the self-aligning platformsystem 800 simplifies both the assembly and the dis-assembly (forrepair, for example) of the platform truck.

With continuing reference to FIGS. 39-41, in the previously describedembodiments (see FIG. 11 for example) the platform 200 was fixedlyattached directly to the deck guides 204, 205, 206, 207. Theself-aligning platform system 800 includes the platform 802 and theplatform self-aligning means 804. Although other methods forself-aligning the platform 802 are possible with this invention, in thepreferred embodiment, the platform self-aligning means 804 includes theplatform 802 having a number of openings 810. Preferably, there are asmany openings 810 as there are deck guides 806. Thus, as shown, theplatform 802 has four openings 810 corresponding to the four deck guides806. Extending from each deck guide 806 is a platform support 812 thatis received within a corresponding platform opening 810 as shown. Ofcourse this invention would work equally well if the platform support812 had an opening (not shown) that received an extending portion (notshown) of the platform 802. The cross-sectional shape of the platformsupport 812 and the opening 810 can be any shape chosen with soundengineering judgment such as circular. In the preferred embodiment,however, they are square shaped. It is also preferred that the platformsupport 812 is hollow to reduce cost and weight while providingsufficient stability. The platform support 812 has an outer dimension Was shown in FIG. 41. It should be noted that the dimension X between theends (or sides) of the platform 802 is less than the dimension Y betweenthe deck guides 806. Thus, an adjustment gap Z is provided between theplatform 802 and the deck guide 806 as seen best in FIG. 41. Preferablyan adjustment gap ratio Z/W is between 0.01 and 5.00 and most preferablybetween 0.05 and 1.00 to provide optimum performance and to minimizematerial weight and cost. In operation, as the platform truckexperiences misalignment forces caused, for example, by theinconsistencies noted above, the platform 802 simply moves along theplatform supports 812 accordingly to relieve all stress. Thisself-aligning movement occurs automatically and may occur along thelength of the platform supports 812 as shown by arrows 814.

The invention has been described with reference to preferredembodiments, obviously, modifications and alternations will occur toothers upon a reading and understanding of the this specification. It isintended to include all such modifications and alterations in so far asthey come within the scope of the appended claims or the equivalentsthereof.

Having thus described the invention, it is now claimed:

What is claimed is:
 1. A platform truck comprising: a frame assembly; afirst guide rod having a first end fixedly connected to a first segmentof said frame assembly and a second end fixedly connected to a secondsegment of said frame assembly; a platform assembly that is selectivelymoveable along said first guide rod that includes, A) a first deck guidethat receives said first guide rod; B) a platform fixedly connected tosaid first deck guide that is constructed so as to hold items thereon;C) a first linear bearing that is received within said first deck guide,said first linear bearing receiving and moveable along said first guiderod; and, D) a first spring support bracket fixedly connected to saidfirst deck guide; and, a first spring having first and second ends forlifting said platform assembly along said first guide rod, said firstend of said first spring being operatively connected to said firstsegment of said frame assembly, said second end of said first springbeing operatively connected to said first spring support bracket.
 2. Theplatform truck of claim 1 further comprising: sound protection means foruse in absorbing sound from said first spring.
 3. The platform truck ofclaim 2 wherein said sound protection means comprises: a foam panel thatsubstantially surround said first spring.
 4. The platform truck of claim1 further comprising: spring restraint means for use in restraining saidfirst spring should said first spring break.
 5. The platform truck ofclaim 4 wherein said spring restraint means comprises: a cable that isreceived within said first spring, said cable having a first endoperatively connected to said first segment of said frame assembly and asecond end operatively connected to said second segment of said frameassembly.
 6. The platform truck of claim 1 further comprising: a firstroller guide operatively connected to said frame assembly, said firstroller guide having a roller surface; and, a first cam roller rotatablyconnected to said first deck guide, said first cam roller rolling alongsaid roller surface of said first roller guide as said platform assemblyis moved along said first guide rod.
 7. The platform truck of claim 6wherein said platform extends from said first deck guide in a firstdirection, said roller surface facing a second direction that issubstantially opposite to said first direction.
 8. The platform truck ofclaim 6 wherein said first roller guide has a channel defining first andsecond roller surfaces, said first cam roller rolling along said firstor said second roller surface as said platform assembly is moved alongsaid first guide rod.
 9. The platform truck of claim 6 furthercomprising: wherein said first deck guide has first and second ends;wherein said first cam roller is rotatably connected to said first endof said first deck guide; and, a second cam roller rotatably connectedto said second end of said first deck guide, said second cam roller alsorolling along said roller surface of said first roller guide as saidplatform assembly is moved along said first guide rod.
 10. The platformtruck of claim 1 wherein said first guide rod is positioned at a pitchangle (PA) with respect to a vertical line, said pitch angle (PA) beingat least 1°.
 11. A dual platform truck comprising: a frame assemblyincluding a first side having first and second segments and a secondside having first and second segments; a first guide rod having a firstend fixedly connected to said first segment of said first side of saidframe assembly and a second end fixedly connected to said second segmentof said first side said frame assembly; a second guide rod having afirst end fixedly connected to said first segment of said second side ofsaid frame assembly and a second end fixedly connected to said secondsegment of said second side said frame assembly; a first platformassembly that is selectively moveable along said first guide rod thatincludes, A) a first deck guide that receives said first guide rod; B) afirst platform fixedly connected to said first deck guide that isconstructed so as to hold items thereon; C) a first linear bearing thatis received within said first deck guide, said first linear bearingreceiving and moveable along said first guide rod; and, D) a firstspring support bracket fixedly connected to said first deck guide; asecond platform assembly that is selectively moveable along said secondguide rod that includes, A) a second deck guide that receives saidsecond guide rod; B) a second platform fixedly connected to said seconddeck guide that is constructed so as to hold items thereon; C) a secondlinear bearing that is received within said second deck guide, saidsecond linear bearing receiving and moveable along said second guiderod; and, D) a second spring support bracket fixedly connected to saidsecond deck guide; a first spring having first and second ends forlifting said first platform assembly along said first guide rod, saidfirst end of said first spring being operatively connected to said firstsegment of said first side of said frame assembly, said second end ofsaid first spring being operatively connected to said first springsupport bracket; and, a second spring having first and second ends forlifting said second platform assembly along said second guide rod, saidfirst side of said second spring being operatively connected to saidfirst segment of said second end of said frame assembly, said second endof said second spring being operatively connected to said second springsupport bracket.
 12. The dual platform truck of claim 11 furthercomprising: wherein said frame assembly includes first and second ends,said first and second segments of said first side of said frame assemblybeing positioned on said first side of said frame assembly, said firstand second segments of said second side of said frame assembly alsobeing positioned on said first end of said frame assembly; wherein saidframe assembly also includes first and second segments on said secondend of said first side and first and second segments on said second endof said second side; a third guide rod having a first end fixedlyconnected to said first segment on said second end of said first side ofsaid frame assembly and a second end fixedly connected to said secondsegment on said second end of said first side of said frame assembly; afourth guide rod having a first end fixedly connected to said firstsegment on said second end of said second side of said frame assemblyand a second end fixedly connected to said second segment on said secondend of said second side of said frame assembly; wherein said firstplatform assembly also includes, A) a third deck guide that receivessaid third guide rod; B) said first platform being fixedly connected tosaid third deck guide; C) a third linear bearing being received withinsaid third deck guide, said third linear bearing receiving and moveablealong said third guide rod; and, D) a third spring support bracketfixedly connected to said third deck guide, wherein said first platformassembly is moveable along said third guide rod; wherein said secondplatform assembly also includes, A) a fourth deck guide that receivessaid fourth guide rod; B) said second platform being fixedly connectedto said fourth deck guide; C) a fourth linear bearing being receivedwithin said fourth deck guide, said fourth linear bearing receiving andmoveable along said fourth guide rod; and, D) a fourth spring supportbracket fixedly connected to said fourth deck guide, wherein said secondplatform assembly is moveable along said fourth guide rod; wherein saidfirst end of said first spring is operatively connected to said firstsegment on said first end of said first side of said frame assembly;wherein said first end of said second spring is operatively connected tosaid first segment on said first end of said second side of said frameassembly; a third spring having first and second ends for lifting saidfirst platform assembly along said third guide rod, said first end ofsaid third spring being operatively connected to said first segment onsaid second end of said first side of said frame assembly, said secondend of said third spring being operatively connected to said thirdspring support bracket; and, a fourth spring having first and secondends for lifting said second platform assembly along said fourth guiderod, said first end of said fourth spring being operatively connected tosaid first segment on said second end of said second side of said frameassembly, said second end of said fourth spring being operativelyconnected to said fourth spring support bracket.
 13. The dual platformtruck of claim 12 further comprising: a first roller guide operativelyconnected to said first end of said first side of said frame assemblyand having a roller surface; a second roller guide operatively connectedto said first end of said second side of said frame assembly and havinga roller surface; a third roller guide operatively connected to saidsecond end of said first side of said frame assembly and having a rollersurface; a fourth roller guide operatively connected to said second endof said second side of said frame assembly and having a roller surface;and, first, second, third and fourth cam rollers rotatably connected tosaid first, second, third and fourth deck guides respectively, saidfirst and third cam rollers rolling along said roller surfaces of saidfirst and third roller guides respectively as said first platformassembly is moved along said first and third guide rods, said second andfourth cam rollers rolling along said roller surfaces of said second andfourth roller guides respectively as said second platform assembly ismoved along said second and fourth guide rods.
 14. The dual platformtruck of claim 13 wherein said first and third guide rods aresubstantially parallel and are positioned at a first pitch angle (PA1)with respect to a vertical line that is at least 1°, said second andfourth guide rods being substantially parallel and being positioned at asecond pitch angle (PA2) with respect to said vertical line that is atleast 1°.
 15. A handtruck comprising: a frame assembly including top andbottom portions and comprising a handle; at least a first wheelrotatably connected to said bottom portion of said frame assembly, saidhandtruck being selectively pivotable about said at least first wheelduring normal operation; a first guide rod having a first end fixedlyconnected to a first segment of said frame assembly and a second endfixedly connected to a second segment of said frame assembly; a platformassembly that is selectively moveable along said first guide rod thatincludes, A) a first deck guide that receives said first guide rod; B) aplatform fixedly connected to said first deck guide that is constructedso as to hold items thereon; C) a first linear bearing that is receivedwithin said first deck guide, said first linear bearing receiving andmoveable along said first guide rod; and, D) a spring support bracketfixedly connected to said first deck guide; and, a first spring havingfirst and second ends for lifting said platform assembly along saidfirst guide rod, said first end of said first spring being operativelyconnected to said first segment of said frame assembly, said second endof said first spring being operatively connected to said first springsupport bracket.
 16. The handtruck of claim 15 further comprising: asecond guide rod having a first end fixedly connected to said firstsegment and a second end fixedly connected to said second segment; saidplatform assembly being moveable along said first and second guide rods,said platform assembly further comprising, A) a second deck guide thatreceives said second guide rod; B) said platform being fixedly connectedto said second deck guide; C) a second linear bearing that is receivedwithin said second deck guide, said second linear bearing receiving andmoveable along said second guide rod; and, D) said second deck guidebeing fixedly connected to said spring support bracket; and, a secondspring having first and second ends for lifting said platform assemblyalong said second guide rod, said first end of said first spring beingoperatively connected to said first segment of said frame assembly, saidsecond end of said second spring being operatively connected to saidspring support bracket.
 17. The handtruck of claim 16 furthercomprising: a third linear bearing that is received within said firstdeck guide, said third linear bearing receiving and moveable along saidfirst guide rod; and, a fourth linear bearing that is received withinsaid second deck guide, said fourth linear bearing receiving andmoveable along said second guide rod.
 18. The handtruck of claim 15further comprising: a latch system for use in selectively preventingsaid platform assembly from moving along said first guide rod.
 19. Thehandtruck of claim 18 wherein said latch system comprises: a recoil unitthat is mounted to said frame assembly; a connection member having afirst end operatively connected to said platform assembly and a secondend operatively connected to said recoil unit; and, locking means forselectively locking said latch system.
 20. The handtruck of claim 19wherein said locking means comprises a foot pedal operatively connectedto said recoil unit.
 21. The handtruck of claim 15 further comprising:damping means for use in damping the spring force of said first spring.22. The handtruck of claim 21 wherein said damping means comprises: anadjustment means for use in adjusting the degree of damping provided bysaid damping means.
 23. The handtruck of claim 22 wherein said dampingmeans comprises: a hydraulic cylinder operatively attached to said frameassembly.
 24. The handtruck of claim 21 wherein said damping meanscomprises: a support rod operatively attached to said frame assembly;and, a first damper having a first end pivotably attached to said firstdeck guide and a second end frictionally contacting a first side of saidsupport rod.
 25. The handtruck of claim 24 wherein said damping meansfurther comprises: a second damper having a first end pivotably attachedto said first deck guide and a second end frictionally contacting asecond side of said support rod; and, biasing means for biasing saidfirst and second ends of said first and second dampers against saidsupport rod.
 26. The platform truck of claim 1 further comprising: alatch system for use in selectively preventing said platform assemblyfrom moving along said first guide rod.
 27. The platform truck of claim26 wherein said latch system comprises: a recoil unit that is mounted tosaid frame assembly; a connection member having a first end operativelyconnected to said platform assembly and a second end operativelyconnected to said recoil unit; and, locking means for selectivelylocking said latch system.
 28. The platform truck of claim 27 furthercomprising: damping means for use in damping the spring force of saidfirst spring.
 29. A platform truck comprising: a frame assembly; a firstguide rod having a first end fixedly connected to a first segment ofsaid frame assembly and a second end fixedly connected to a secondsegment of said frame assembly; a platform assembly that is selectivelymoveable along said first guide rod comprising: A) a first deck guidethat receives said first guide rod; B) a platform fixedly connected tosaid first deck guide that is constructed so as to hold items thereon;lifting means for lifting said platform assembly along said first guiderod; and, a latch system for use in selectively preventing said platformassembly from moving along said first guide rod, said latch systemcomprising: A) a recoil unit that is mounted to said frame assembly; B)a connection member having a first end operatively connected to saidplatform assembly and a second end operatively connected to said recoilunit; and, C) locking means for selectively locking said latch system.30. The platform truck of claim 29 further comprising: damping means foruse in damping the lifting means.
 31. A platform truck comprising: aframe assembly; a first guide rod having a first end fixedly connectedto a first segment of said frame assembly and a second end fixedlyconnected to a second segment of said frame assembly; a self-aligningplatform assembly that is selectively moveable along said first guiderod comprising: A) a first deck guide that receives said first guiderod; B) a platform constructed so as to hold items thereon; and, C)platform self-aligning means for automatically aligning said platformwith respect to said first deck guide; a first spring support bracketfixedly connected to said first deck guide; and, a first spring havingfirst and second ends for lifting said platform assembly along saidfirst guide rod, said first end of said first spring being operativelyconnected to said first segment of said frame assembly, said second endof said first spring being operatively connected to said first springsupport bracket.
 32. A platform truck comprising: a frame assembly; afirst guide rod having a first end fixedly connected to a first segmentof said frame assembly and a second end fixedly connected to a secondsegment of said frame assembly; a self-aligning platform assembly thatis selectively moveable along said first guide rod comprising: A) afirst deck guide that receives said first guide rod; B) a platformconstructed so as to hold items thereon; and, C) platform self-aligningmeans for automatically aligning said platform with respect to saidfirst deck guide; a first platform support extending from said firstdeck guide; and, said platform having a first end with a first openingfor selectively receiving said first platform support, said platformbeing selectively moveable along said first platform support.
 33. Theplatform truck of claim 34 further comprising: a second guide rod havinga first end fixedly connected to a third segment of said frame assemblyand a second end fixedly connected to a fourth segment of said frameassembly; a second deck guide that receives said second guide rod; asecond platform support extending from said second deck guide; and, saidplatform having a second end with a second opening for selectivelyreceiving said second platform support, said platform being selectivelymoveable along said second platform support.
 34. The platform truck ofclaim 33 wherein said second platform support has an outer dimension(W), said platform has a dimension (X) between said first and secondends of said platform and said platform truck has a dimension (Y)between said first and second deck guides, said dimensions (X) and (Y)forming adjustment gaps (Z) between said platform and said first andsecond deck guides, an adjustment gap ratio Z/W is between 0.05 and1.00.
 35. A method of aligning a platform comprising the steps of:providing a platform truck that includes a frame assembly and a firstguide rod having a first end fixedly connected to a first segment of theframe assembly and a second end fixedly connected to a second segment ofthe frame assembly; providing a self-aligning platform assembly that isselectively moveable along the first guide rod and that includes a firstdeck guide that receives the first guide rod, a platform constructed soas to hold items thereon and platform self-aligning means; providing afirst platform support extending from the first deck guide; and,providing a first end of the platform with a first opening that receivesthe first platform support; applying a misalignment force to theplatform truck; and, automatically aligning the platform with respect tothe first deck guide by the platform along the first platform support.